If you don't believe me, I'll show it to you:
According to a reliable source like
this one, the number of rapes in New York was 3169 in 2006. The population is some 18 million.
In oslo, according to
this article there were 235 reported rapes in 2006 with a population of some 500.000.
Multiply 235 with 36, and you get 8460. Divide 8460 by 3169 and you get a little over 2,5 and not 6...
But that doesn't give a very good picture, as with anything involving rape and statistics, due to the fact that the vast number of rapes never gets reported and the numbers are pulled from two different agencies. Also, I don't really know what the new york numbers are, if they're convictions or rapes reported to the police.